In one known component mounting method in which two or more objects are directly bonded together, the objects are placed inside a vacuum chamber and cleaned by directing energy waves onto their surfaces in a low-pressure gas atmosphere, after which the objects are faced opposite each other and pressed together, with the chamber sealed vacuum, or sealed with inactive gas or other gas that does not react with the objects (see, for example, Patent Document 1).
In another known bonding method in which Au bumps of electronic components are joined by metal bonding with Au film on the surface of connection terminals of the substrate, the substrate and electronic components are placed in a vacuum atmosphere inside a chamber, the Au bumps on the electronic components and Au film on the surface of the connection terminals of the substrate are cleaned by unidirectionally accelerated energy particles such as fast atom beam or ion beam, and while the vacuum atmosphere, or a certain gas atmosphere, is maintained, the bumps and connection terminals that have been activated by the cleaning are brought into contact with each other and pressure is applied, whereby they are joined under room temperature (see, for example, Patent Document 2). This conventional technique claims that bonding is also possible in the atmosphere, and within ten minutes during which the activated state achieved by the cleaning process can be maintained, bonding is performed in a temperature range of from room temperature to 150° C.
Patent Document 1: Japanese Patent Publication No. 2001-351892
Patent Document 2: Japanese Patent Publication No. 2003-197673